Personal care compositions contain a variety of additives that provide a wide array of benefits to the composition. Unsaturated fatty acids are one of such additives, and known to be important for the preservation of the skin-barrier function and water content of skin. Due to their structure, unsaturated fatty acids can enhance the fluidity of cell membranes, which lead to a more moistened and smoother skin. Unsaturated fatty acids, however, undergo a chemical change known as auto-oxidation, wherein the double bonds of an unsaturated fatty acid can undergo cleavage in the presence of oxygen and free radicals, releasing volatile aldehydes and ketones. Such auto-oxidation can often result in rancidity of the substance, which is associated with an unpleasant odor and color. Accordingly, formulators have utilized antioxidant cocktails and nitrogen packaging processes to decrease peroxidation of unsaturated fatty acids.
Inhibition of oxidation of polyunsaturated lipids has been addressed in the art. For example, U.S. Pat. No. 6,428,461 discloses mixing polyunsaturated lipids with a combination of polyamines such as spermidine, putrescine, or mixtures thereof, in food processing applications. The prior art falls short, however, of disclosing optimal antioxidants for unsaturated fatty acids in personal care compositions.
Consequently, there is a continuing need to develop new methods of inhibiting oxidation of unsaturated fatty acids in personal care compositions.